LILIACEAE 



475 



are homogamous, and not protogynous, so that automatic self-pollination is possible 

 from the beginning of anthesis. Kerner, however, describes the flowers as proto- 

 gynous. If insects visit them, cross- 

 pollination is favoured, as the visitor 

 generally brushes against a stigma with 

 one side of its body and the anthers 

 with the other. Fresh specimens ob- 

 served by Vanhoffen in Greenland bore 

 white flowers {cf. Abromeit, 'Bot. Er- 

 geb. von Drygalski's Gronlandsexped.,' 

 P- 79)- 



Visitors. Herm. Miiller (Alps) 

 observed 2 Muscids and a small lepi- 

 dopterid. 



2831. T. coccinea Rich. (Abro- 

 meit, op. cit., pp. 79-80.) This species 

 has denser inflorescences than the last 

 one, and the flowers are typically of a purple-red colour. 



Fig. 408. Tqfieldia calycuiala, Wahlenb., and 7\ 

 palusiris, Huds. (after Herm. Miiller). A. Flower of 

 T. calyculata. B. Do. of T. palusiris, towards even- 

 ing. C. Do., in the morning (x 7). a and a', closed and 

 dehisced anthers ; , nectary ; st, stigma. 



919. Zygadenus Michx. 



2832. Z. elegans Pursh. The flowers of this species are dirty-white in colour, 

 with green blotches. 



Visitors. Plateau observed ants, other small Hymenoptera, and hover-flies. 



CXV. ORDER PONTEDERIACEAE BENTH. ET HOOK. 



920. Monochoria Presl. 



Kuhn (Bot. Ztg., Leipzig, xxv, 1867) states that some species of this genus bear 

 cleistogamous flowers. 



921. Pontederia L. 



Fritz Miiller describes species of this genus as trimorphous (Jenaische Zs. Natw., 

 vi, 1871, pp. 74-8). 



922. Heteranthera Ruiz et Pav. 



2833. H. reniformis Ruiz et Pav. (Herm. Miiller, Kosmos, Leipzig, vii, 1880; 

 Hildebrand, Ber. D. bot. Ges., Berlin, i, 1883.) Herm. Muller says that this species 

 possesses two kinds of stamens, one long one with pale-blue anthers, and two short 

 ones with yellow pollen. When the small white flower opens, the former bends to 

 the left, and the style to the right. Should insect-visits fail, self-pollination takes 

 place. Hildebrand confirms the latter statement. 



2834. H. zosteraefolia Mart. (Hildebrand, Jahrb. f. Syst., vi, 1885.) In this 

 species automatic self-pollination is at first excluded, but can take place later when 



